I should say it seems to go rich. it gives me a 171 which says its lean but it smells and the sensor comes out sooty

 

maybe the 171 come from a dying sensor but what does the rich or smelly condition come from?

 

Oh, right, sorry I forgot. They are dying at 0 volts - which tells the ECM that the engine is full lean, so it adds fuel when it does not need to - and goes full rich. If you disconnect the dead sensor it should revert to SD programming.

 

yep I did and it runs smoothly and no smell. so now i'll drive it and watch my coolant closely

 

to close this out i installed a denso O2 sensor and have not had another failure. i also installed new valve cover gaskets a few weeks later to prevent the oil from getting on the sensor